Bikesharing programs, like SmartBike in Washington, D.C., are a hot topic at TRB's Annual Meeting. Photo by Hugger Industries.

One of the most interesting sessions I attended on my first day of the TRB annual meeting outlined current research on market shares and modal impacts of carsharing and bike sharing.

Elliot Martin and his fellow researchers from the University of California, Berkeley found that carsharing impacts vehicle ownership, reducing demand for vehicles. Using a before-after survey of members of several carsharing organizations, the group observed that vehicles were shed after a household joined the carsharing organization. Households had an average of .47 vehicles per household before joining, they only had .24 vehicles per household after becoming members. The most common transition was from one car to none. By aggregating these impacts, the researchers estimated that 9-13 vehicles are removed from the road for each carsharing vehicle deployed. Though the study population was a self-selecting group of urban consumers and vehicle shedding numbers were based in part on hypothetical “would have” questions, it was interesting to see the effects of carsharing quantified.

Another presenter from Montreal’s Ecole Polytechnique examined the relationship between neighborhood attributes and carsharing’s market share in her home city. Her results showed that connectivity to public transit, the age of the transit station and the average employment rate had a positive impact on market share, while distance to the neighborhood center and household size had a negative relationship with market share. These models showed no signs of market saturation, indicating that carsharing has the potential to attract a greater clientele in the study area.

Susan Shaheen, also from the University of California, Berkeley, gave an overview of the history and outlook of bike sharing across four continents. She outlined four generations of bike sharing:

First generation: Typically free systems with brightly-colored bikes

This generation was exemplified by Amsterdam’s White Bike Program (1965), which eventually failed due to vandalism and theft